If you try to rewrite the two equations in the form then you will get:
You know that the slope is the coefficient of x i.e. the number a.
for the first question, no equation has a slope of -1
for the second question, you have to know that a vertical line has a slope of infinity and it can't be represented in the form . It is rather represented as . So no equation from the given satisfies this condition.
for the third question, you can see that the second equation has a slope of 1.
for the fourth question, you have to know that a horizontal line has a slope of 0 and it is represented as . So, no equation from the given satisfies this condition.